381. Stefan-Boltzman law applies to __________ body.
Black
White
Grey
Any colour
✅ The correct answer is option A.
Heat Transfer MCQs
382. For evaporation of viscous solution in a multiple effect evaporator, the prefered feeding scheme is
Forward
Backward
Parallel
None of these
✅ The correct answer is option B.
383. Which of the following is generally considered as opaque surface towards radiations?
Gases
Solids
Liquids
Both B and C
✅ The correct answer is option D.
384. Rate of crystallisation does not depend upon the
Extent of supersaturation
Turbulence within the solution
Number and active surface area of the crystals
None of these
✅ The correct answer is option D.
385. Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is
0.2
0.4
0.6
0.8
✅ The correct answer is option C.
386. Vent pipes are provided in a condenser to
Remove non-condensable gases
Purge the condenser
Facilitate easy cleaning of tubes
None of these
✅ The correct answer is option A.
387. The advantage of backward feed multiple effect evaporators over forward feed units is that
Heat sensitive material can be handled
There is no additional cost of pumping
Most concentrated liquid is at highest temperature
Equal heat transfer co-efficients exist in various effects
✅ The correct answer is option C.
388. The purpose of floating head in a heat exchanger is to
Avoid buckling of tubes
Provide support for tubes
Decrease the pressure drop
Facilitate its lengthening, if needed
✅ The correct answer is option A.
389. Nucleate boiling is promoted
On polished surfaces
On rough surfaces
In the absence of agitation
None of these
✅ The correct answer is option B.
390. For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
Increases
Decreases
Remains constant
Passes through a maxima
✅ The correct answer is option D.